The plant Morinda lucida falls under the family Rubiaceae known to have wide usage in traditional medicine. Morinda lucida is a tropical West African tree of medium-size about 18–25 m tall, the bark is grey to brown in colour, flowers are white in colour, the fruit is a drupe, seed is ellipsoid, yellowish and soft. The purpose of this work is to determine the antimicrobial properties of Morinda lucida against Mycobacterium species, a very virulent and infectious organism, isolated from the Chest Hospital, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. The method used to determine the antimicrobial potency of the plant extracts is the Agar well diffusion method. The antibacterial potency of Ethyl acetate and ethanol extracts of Morinda lucida leaf, stem, and bark were tested against mycobacterium species including Mycobacterium fortuitum (ATCC 6841), Mycobacterium smegmatis (ATCC 19420, Mycobacterium abscessus (ATCC 19977), and Mycobacterium phlei (ATCC 19240). All extracts exhibited various degree of antibacterial potency against the test organisms with the ethyl acetate extracts of the leaf and bark being the most active and ethanol extracts were the least active. The zone of inhibition of ethyl acetate leaf, bark and stem extracts range between 3.0 mm to 18.0 mm and the zone of inhibition of ethanol leaf, bark and stem extracts ranges between 1.0 mm to 10.0 mm respectively.
